A Paternal Methylation Error in the Congenital Hydrocephalic Texas (H-Tx) Rat Is Partially Rescued with Natural Folate Supplements.

Folate deficiencies, folate imbalance and associated abnormal methylation are associated with birth defects, developmental delays, neurological conditions and diseases. In the hydrocephalic Texas (H-Tx) rat, 10-formyl tetrahydrofolate dehydrogenase (FDH) is reduced or absent from the CSF and the nuclei of cells in the brain and liver and this is correlated with decreased DNA methylation. In the present study, we tested whether impaired folate metabolism or methylation exists in sexually mature, unaffected H-Tx rats, which may explain the propagation of hydrocephalus in their offspring. We compared normal Sprague Dawley (SD, n = 6) rats with untreated H-Tx (uH-Tx, n = 6 and folate-treated H-Tx (TrH-Tx, n = 4). Structural abnormalities were observed in the testis of uH-Tx rats, with decreased methylation, increased demethylation, and cell death, particularly of sperm. FDH and FRα protein expression was increased in uH-Tx males but not in folate-treated males but tissue folate levels were unchanged. 5-Methylcytosine was significantly reduced in untreated and partially restored in treated individuals, while 5-hydroxymethylcytosine was not significantly changed. Similarly, a decrease in DNA-methyltransferase-1 expression in uH-Tx rats was partially reversed with treatment. The data expose a significant germline methylation error in unaffected adult male H-Tx rats from which hydrocephalic offspring are obtained. Reduced methylation in the testis and sperm was partially recovered by treatment with folate supplements leading us to conclude that this neurological disorder may not be completely eradicated by maternal supplementation alone.

Prenatal work-up, associated anomalies and postnatal outcomes of foetuses with 9-9.9 mm cerebral ventricular atria width.

OBJECTIVE: To analyse prenatal work-up, associated anomalies and postnatal outcomes of foetuses with cerebral lateral ventricular width 9-9.9 mm. METHOD: This retrospective, observational, case-control study included 121 foetuses with initial presentation of isolated cerebral lateral ventricular width 9-9.9 mm detected during routine ultrasound scans, 21-24 weeks' gestation, in a tertiary referral centre, January 2001-December 2018. Controls included 123 foetuses with lateral ventricular width <9 mm measured under the same parameters. Clinical characteristics, obstetrical history, ultrasound findings, prenatal work-up and pregnancy outcomes were collected from medical records. Information about postnatal functional and neurodevelopmental sequelae were obtained from telephone-based questionnaires. RESULTS: The study group had more males (82/116 (70.6%) versus 65/123 (52.8%), p = 0.004), more prenatal testing, including brain magnetic resonance imaging (28/116 (24.1%) versus 0/123 (0%), p < 0.001), echocardiography (46/116 (39.7%) versus 15/123 (12.2%), p < 0.001) and targeted anomaly scans (102/116 (87.9%) versus 1/123 (0.008%), p < 0.001). Long-term follow-up did not reveal more neurodevelopmental sequelae compared to controls. Gender-based analysis found more males with ventricular dilatation 9-9.9 mm treated for developmental delay compared to females with similar findings (15/82 (18.2%) versus 1/34 (2.9%), p = 0.010). CONCLUSION: Foetuses with 9-9.9 mm cerebral lateral ventricular width versus <9 mm underwent more prenatal testing but had similar rates of neurodevelopmental sequelae.

Resolution of auditory neuropathy spectrum disorder after shunt placement in a patient with hydrocephalus: A case report.

PURPOSE: There have been previous case reports suggesting the resolution of both sensorineural hearing loss and retrocochlear involvement through the management of hydrocephalus with shunt placement. This is a case report of a patient with Auditory Neuropathy Spectrum Disorder (ANSD) that resolved after shunt placement in a patient with hydrocephalus. MATERIALS AND METHODS: Chart review of a single patient with a diagnosis of ANSD and hydrocephalus. Type of audiometric testing and results were document. RESULTS: Patient is an infant who was diagnosed with hydrocephalus at birth and ANSD in the right ear at 3 months of age. Patient underwent shunt placement at 9 months old and had behavioral testing 2 months later. Audiometry showed normal behavioral audiometric thresholds with presence of ipsilateral and contralateral reflexes which is suggestive of resolution of ANSD. CONCLUSIONS: This is a single case report of resolution of ANSD after shunt placement in a patient with hydrocephalus. Close monitoring and repeat audiological evaluation is recommended to follow these patients.

A novel nonsense mutation in the L1CAM gene responsible for X-linked congenital hydrocephalus.

BACKGROUND: Congenital hydrocephalus is a descriptive diagnosis of symptoms, that are present for numerous reasons, including chromosomal disorders, genetic mutations, intrauterine infection and hemorrhage, amongst other factors. Mutation of L1CAM gene is the most frequent cause of congenital hydrocephalus, contributing to approximately 30% of X-linked congenital hydrocephalus. METHODS: In the present study, we used whole-exome sequencing and Sanger sequencing to investigate an aborted male fetus present with severe congenital hydrocephalus at 24 weeks of gestation, whose mother had a history of two previous voluntary terminations of pregnancies as a result of hydrocephalus. Magnetic resonance imaging, an autopsy and electron microscopy were performed and the phenotypic changes were described. RESULTS: Whole-exome sequencing in the fetus, as well as variant segregation analysis, revealed a novel maternally derived hemizygous nonsense mutation (c.2865G>A; p. Y955*) in exon 21 of the L1CAM gene (NM_000425.4). Severe hydrocephalus was observed along with marked dilatation of lateral ventricles. An electron micrograph of the surface of lateral ventricle walls revealed a lack of ependymal cilia. CONCLUSION: The present study suggests that L1CAM mutation screening should be considered for a male fetus with isolated hydrocephalus, especially with a family history, which could facilitate prenatal diagnosis in a subsequent pregnancy.

Maternal mosaicism underlies the inheritance of a rare germline AKT3 variant which is responsible for megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome in two Roma half-siblings.

Megalencephaly-polymicrogyria-polydactyly-hydrocephalus (MPPH) syndrome is a developmental brain disorder characterized by an enlarged brain size with bilateral perisylvian polymicrogyria and a variable degree of ventriculomegaly. MPPH syndrome is associated with oromotor dysfunction, epilepsy, intellectual disability and postaxial hexadactyly. The molecular diagnosis of this disorder is established by the identification of a pathogenic variant in either AKT3, CCND2 or PIK3R2. Previously reported AKT3 variants are associated with various brain abnormalities and may lead to megalencephaly. MPPH syndrome is usually due to germline pathogenic AKT3 variants. Somatic mosaic pathogenic variants associated with hemimegalencephaly, which is similar to MPPH, have also been observed. A Hungarian Roma family with two half-siblings, which present with intellectual disability, dysmorphic features, epilepsy, brain malformations, and megalencephaly was studied. Whole exome sequencing (WES) analysis was performed. WES analysis revealed a heterozygous c.1393C > T p.(Arg465Trp) pathogenic missense AKT3 variant in both affected half-siblings. The variant was verified via Sanger sequencing and was not present in the DNA sample from the healthy mother, which was derived from peripheral blood, suggesting maternal germline mosaicism. In conclusion, this is the first report in which maternal germline mosaicism of a rare pathogenic AKT3 variant leads to autosomal dominantly inherited MPPH syndrome.

Histologic Appearance of Iatrogenic Obstructive Hydrocephalus in the Fetal Lamb Model.

INTRODUCTION: Documentation of histologic findings associated with congenital hydrocephalus in the fetal lamb model is a critical step in evaluating the efficacy of ventriculoamniotic shunting in the human fetus. METHODS: Four fetal sheep had hydrocephalus induced at approximately 95 days' gestation. Two co-twins remained as controls. The ewes were euthanized at term. The lamb brains were fixed in formalin, paraffin-embedded, stained, and analyzed for markers of neuropathology. Astrocytosis, microgliosis, and axonal loss were assessed with immunocytochemistry for glial fibrillary acidic protein, ionized calcium-binding adapter, and neurofilament/amyloid precursor protein, respectively. Cortical gray matter extracellular matrix was assessed with staining for the lectin Wisteria Floribunda agglutinin. RESULTS: Hydrocephalic lamb brains demonstrated deep white matter damage with loss of projecting axonal tracts in regions physically distorted by hydrocephalus, similar to that seen in hydrocephalic humans. There was no evidence of abnormal neocortical neuronal migration; however, there was evidence for delayed maturation of the neocortical gray matter, possibly from increased intracerebral pressure and subsequent ischemia. Control lamb brains demonstrated none of the above findings. CONCLUSION: This histological approach can be used to further define the mechanism of brain damage associated with hydrocephalus and interpret the efficacy of ventriculoamniotic shunting on fetal lamb brain neuroanatomy.

Prenatal aqueduct stenosis: Association with rhombencephalosynapsis and neonatal outcome.

BACKGROUND AND PURPOSE: To examine prenatal MRI and postnatal imaging in fetuses with congenital aqueductal stenosis (CAS) to determine the frequency of association of rhombencephalosynapsis (RES) and how it may affect neonatal intensive care unit (NICU) course. MATERIALS AND METHODS: A single center IRB-approved retrospective study of children with CAS was performed. Prenatal MRI, postnatal images, and clinical data were reviewed. Statistical analysis was performed with SAS statistical software package version 9.3. RESULTS: Aqueduct obstruction was confirmed for all 30 participants. Hydrocephalus required shunting in all but one (97%). Fifteen neonates had CAS with rhomboencephalosynapsis (RES) (50%). Although neonatal course between the two groups was comparable, 53% of CAS with RES neonates required feeding assistance versus 20% in CAS only (P = 0.128). Shunting in the CAS with RES group occurred at average of 6 days of life versus CAS group at 55 days (P = 0.196). Biometry measurements showed a statistically significant decrease in pons antero-posterior diameter in both groups (CAS only P = 0.0049 and CAS with RES P = 0.0003) when compared with norms for gestational age. CONCLUSION: CAS has a high association with RES. Feeding assistance in the NICU and earlier neurosurgical intervention may be required in patients with CAS who also have RES.

Unexpected eosinophilia in children affected by hydrocephalus accompanied with shunt infection.

PURPOSE: The aim of the article is to describe an immunological reaction to shunt infection in children with hydrocephalus. The main cause of shunt infection involves methicillin resistant Staphylococcus epidermidis (Bhatia et al. Indian J Med Microbiol 35:120-123, 2017; Hayhurst et al. Childs Nerv Syst 24:557-562, 2008; Martínez-Lage et al. Childs Nerv Syst 26: 1795-1798, 2010; Simon et al. PLoS One, 2014; Snowden et al. PLoS One 8:e84089, 2013; Turgut et al. Pediatr Neurosurg 41:131-136, 2005), a bacterial strain which is responsible for the formation of biofilm on contaminated catheters (Snowden et al. PLoS One 8:e84089, 2013; Stevens et al. Br J of Neurosurg 26: 792-797, 2012). METHODS: The study group involved 30 children with congenital hydrocephalus after shunt system implantation, whose procedures were complicated by S. epidermidis implant infection. Thirty children with congenital hydrocephalus awaiting their first-time shunt implantation formed the control group. The level of eosinophils in peripheral blood was assessed in both groups. Cerebrospinal fluid (CSF) was examined for protein level, pleocytosis, interleukins, CCL26/Eotaxin-3, IL-5, IL-6, CCL11/Eotaxin-1, CCL3/MIP-1a, and MBP. Three measurements were performed in the study group. The first measurement was obtained at the time of shunt infection diagnosis, the second one at the time of the first sterile shunt, and the third one at the time of shunt reimplantation. In the control group, blood and CSF samples were taken once, at the time of shunt implantation. RESULTS: In the clinical material, the highest values of eosinophils in peripheral blood and CSF pleocytosis were observed in the second measurement. It was accompanied by an increase in the majority of analyzed CSF interleukins. CONCLUSION: CSF pleocytosis observed in the study group shortly after CSF sterilization is presumably related to an allergic reaction to Staphylococcus epidermidis, the causative agent of ventriculoperitoneal shunt infection.

Isolated Post-Shunt Metopic Synostosis and Neural Tube Defects.

BACKGROUND: Craniosynostosis is an uncommon complication after shunting procedures for congenital hydrocephalus. We report a case of a child with myelomeningocele and normocephaly at the time of birth. She underwent ventricular shunting for Chiari malformation and hydrocephalus at 3 days of age. An immediate postoperative CT scan confirmed all sutures were open. Serial CT scans document an open metopic suture at 2 months, closed metopic suture at 5 months, and trigonocephaly at 11 months with concomitant slit ventricle syndrome, and collapsed lateral and third ventricles. METHODS: An Ovid MEDLINE search within the dates of 1948 through 2017, using the keywords "synostosis AND shunt" was carried out. A tabulation of all patients and their respective synostosis patterns were recorded. RESULTS: We identified 8 case series and 2 case reports during 43 years (1966-2017). Seventy-eight patients with 79 suture synostosis patterns were identified (one patient underwent a second cranial reconstruction for identification of a separate, newly formed synostosis). Eighteen (30.5%) cases were associated with a neural tube defect (NTD). Patients with NTD and secondary craniosynostosis had on average earlier age of shunt placement (P = 0.001), craniosynostosis presentation (P = 0.146), and cranioplasty (P = 0.325) than secondary craniosynostosis patients without NTD. CONCLUSIONS: Ventricular shunt drainage in treating hydrocephalus rarely may lead to early synostosis and cranial deformity, especially in patients with NTDs. Early shunt placement poses significant risk in patients with NTD. Close follow-up may be necessary to evaluate overdrainage and cranial deformity after shunting procedures.

Congenital Hydrocephalus: Gómez-López-Hernández syndrome. An underdiagnosed Syndrome. A clinical case. / Hidrocefalia Congénita: Síndrome de Gómez-López-Hernández, un síndrome subdiagnosticado. Caso clínico.

INTRODUCTION: Hydrocephalus is defined as complex conditions influenced by genetic and environmental factors. Excluding hydrocephalus acquired from infection or brain tumors, congenital hydrocephalus with a genetic cause may occur isolated (hydrocephalus isolated, pure or non-syndromatic) or as a component of a genetic syndrome (syndromic hydrocephalus). OBJECTIVE: To present a syndromic congenital hydrocephalus with a known diagnosis, in order to be considered in the study of this pathology and to perform a review of hydrocephaly with a genetic cause. CLINICAL CASE: Preschool with a prenatal diagnosis of hydrocephalus and rhombencephalosynapsis, karyotype and study of TORCH was normal. At the moment of birth, the prenatal diagnoses were confirmed and a malformation of cerebral cortical development was excluded. During the first week of life, perito neal ventricle shunt was performed. A reevaluation at age 4, the absence of corneal reflexes bilate ral parietal and congenital focal alopecia associated with rhombencephalosynapsis, meet definitive criteria for cerebello-trigeminal-dermal displasia or Gómez-López-Hernández syndrome (GLHS). CONCLUSIONS: GLHS is an uncommon neurocutaneous syndrome, possibly a sporadic condition that is underdiagnosed. Due to the new imaging and genetic technologies pre and post-natal, today it is possible to achieve a better and more accurate diagnosis of hydrocephalus with a genetic origin, in which the high suspicion of teams of clinical specialists is essential. Without accurate diagnosis, we can not access to a long-term prognosis, prevention of aggregate morbidity or an adequate genetic counseling, which are required in today's pediatrics.

Ventriculoperitoneal shunt for treatment of hydrocephalus in a French bulldog puppy.

A 6.5-week-old bulldog was presented with lethargy, anorexia, and stunted growth. A domed skull, ventrolateral strabismus, hypermetria, and delayed hopping were observed. Congenital hydrocephalus was diagnosed and a ventriculoperitoneal shunt was placed. After surgery, a shunt obstruction occurred but resolved with treatment. The puppy responded well and neurological deficits continued to improve after surgery.

Dérivation ventriculo-péritonéale pour le traitement de l'hydrocéphalie chez un chiot Bouledogue français. Un Bouledogue âgé de 6,5 semaines a été présenté pour de l'abattement, de l'anorexie et une croissance retardée. Un crâne en forme de dôme, du strabisme ventrolatéral, de l'hypermétrie et du sautillement retardé ont été observés. Une hydrocéphalie congénitale a été diagnostiquée et une dérivation ventriculo-péritonéale a été placée. Après la chirurgie, une obstruction de la dérivation s'est produite mais s'est résorbée après un traitement. Le chiot a bien répondu et les déficits neurologiques ont continué de s'améliorer après la chirurgie.(Traduit par Isabelle Vallières).

Experience of ventriculo-peritoneal shunt insertion in late presenting congenital hydrocephalus.

OBJECTIVE: To evaluate the outcomes of insertion of ventriculo-peritoneal shunts in paediatric neglected hydrocephalus. METHODS: The quasi-experimental study was conducted at the Combined Military Hospital, Rawalpindi, from January 2012 to June 2014, and comprised infants of both genders who presented late with congenital hydrocephalus, having fronto-occipital circumference more than 98 percentile of matched age group. Pre-operative assessment was based upon detailed history, clinical examination, laboratory investigations and computed tomography scan of head. After insertion of ventriculo-peritoneal shunt, patients were followed up for outcomes. Data was analysed using SPSS 17. RESULTS: Of the 30 infants, 12(40%) were girls and 18(60%) were boys. Overall mean age was 7.73±1.41 months (range: 5-10 months). Mean fronto-occipital circumference was 54.30±3.08. Cerebrospinal fluid infection was documented in 12(40%). Abdominal wound complications were observed in 7(23.3%) infants. Ventriculo-peritoneal shunt was removed in 18(60%) and eventually replaced in 18(60%). In-hospital mortality on account of complications was encountered in 13(43.3%). Correlation of fronto-occipital circumference to mortality was significant (p=0.001). CONCLUSIONS: To shunt or not to shunt remains a dilemma for poor-risk infants, but timely reporting of infants with hydrocephalus, proper case selection may improve the outcome of surgical intervention.

Quantifying the Disability from Congenital Anomalies Averted Through Pediatric Surgery: A Cross-Sectional Comparison of a Pediatric Surgical Unit in Kenya and Canada.

BACKGROUND: Pediatric surgical practice is different in low- and middle-income countries as compared to North America. While resources are limited, the impact of pediatric surgical procedures is significant. The objective of this study was to calculate and compare disability-adjusted life years (DALYs) averted in a Kenyan and Canadian surgical unit for a subset of pediatric congenital anomalies. METHODS: Medical records of children having undergone surgical procedures for 13 congenital conditions in both surgical units were collected over 12 months. DALYs for each condition were calculated using previously obtained disability weights derived in each country. Age-adjusted life expectancy rates from the WHO were used to determine years of life lost. Risk of permanent disability without surgery and probability of successful treatment values were obtained from the literature and included in the DALY calculation. RESULTS: The conditions accounting for the largest total number of averted DALYs in Kenya were hydrocephalus (60.8%) and spina bifida (18.1%), whereas in Canada they were hydrocephalus (24.2%) and undescended testes (19.2%). A total of 23,169 DALYs were averted through 1042 surgical procedures (22.2 DALYs per procedure) during the study period in Kenya, compared to 5497 DALYs through 373 procedures (14.7 DALYs per procedure) in Canada. CONCLUSIONS: Using recent developments in burden of disease measurement, the results point to the significant impact of pediatric surgical centers in addressing the global burden of congenital surgical disease. The study carries significant implications for resource allocation and training.

CSF hydrothorax: An unusual cause of pleural effusion.

A 20-year-old male with hydrocephalus managed with a ventriculoperitoneal shunt (VP) was diagnosed with a cerebrospinal fluid (CSF) pleural effusion. Imaging studies revealed an intrathoracic course of a disconnected VP shunt. Physicians should consider CSF effusion in their differential diagnosis in patients with a VP shunt and an unexplained pleural effusion.

Unilateral cortical hyperexcitability in congenital hydrocephalus: a TMS study.

INTRODUCTION: Changes in cortical excitability are considered to play an important role in promoting brain plasticity both in healthy people and in neurological diseases. Hydrocephalus is a brain development disorder related to an excessive accumulation of cerebrospinal fluid (CSF) in the ventricular system. The functional relevance of cortical structural changes described in this disease is largely unexplored in human. We investigated cortical excitability using multimodal transcranial magnetic stimulation (TMS) in a case of congenital hydrocephalus with almost no neurological signs. METHODS: A caucasian 40 years old, ambidextrous and multilingual woman affected by occult spina bifida and congenital symmetrical hydrocephalous underwent a TMS study. The intracortical and interhemispheric paired pulse paradigms were used, together with the mapping technique. RESULTS: No significant differences were found in the resting motor thresholds between the two hemispheres. Instead, the intracortical excitability curves were statistically different between the two hemispheres (with short intracortical inhibition (SICI) being strongly reduced and intracortical facilitation (ICF) enhanced in the right one), and the interhemispheric curves showed a general hyper-excitability on the right hemisphere (when conditioned by the left one) and a general hypo-excitability in the left hemisphere (when conditioned by the right one). It is noteworthy that an asymmetric right hemisphere (RH) change of excitability was observed by means of mapping technique. CONCLUSION: We hypothesize that in this ambidextrous subject, the observed RH hyper-excitability could represent a mechanism of plasticity to preserve functionality of specific brain areas possibly devoted to some special skills, such as multilingualism.

Case report of a de novo brainstem arteriovenous malformation in an 18-year-old male and review of the literature.

De novo intracerebral arteriovenous malformations (AVMs) are exceedingly rare with only seven reported cases in the literature. Although generally considered congenital by nature, the lesions do not manifest themselves clinically until the third or fourth decades of life. However, with the advent of improved imaging modalities and more frequent surveillance, an increasing number of de novo cases are being found challenging the concept AVMs develop in the perinatal/antenatal period. Alternatively, this phenomenon could represent a distinct entity in which lesion development occurs after birth. A PubMed search of "de novo cerebral arteriovenous malformation" was performed in which seven reported cases were found. The mean age at diagnosis was 14.7 years with a mean follow-up imaging study of 5.8 years. Lesion location was supratentorial in all previously described cases. This case involves an 18-year-old male with congenital hydrocephalus and seizures diagnosed at 7 months of age. The patient underwent a ventriculoperitoneal shunt and was followed frequently by a neurologist. The last diagnostic imaging was an unremarkable MRI of the brain at age 12. Seven years later, the patient presented with an intracerebral hemorrhage. A CT angiogram demonstrated a large brainstem AVM with an intraparenchymal hemorrhage and intraventricular extension. This case is unique in that it is the first infratentorial de novo AVM. The congenital nature of AVMs is challenged with the increasingly described series of patients with previously documented normal radiographic imaging. This suggests there may be a subset of patients genetically predisposed to postnatal development of AVMs.

Rapid deterioration of primary fourth ventricular outlet obstruction resulting in syndrome of inappropriate antidiuretic hormone secretion.

Fourth ventricular outlet obstruction (FVOO) is a rare cause of obstructive hydrocephalus. Although FVOO accompanied by malformative syndrome and secondary causes of obstruction are common, there are few reports of primary FVOO (PFVOO). The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a rare presenting feature of hydrocephalus. A 1-year, 8-month-old boy with a normal head circumference developed SIADH accompanied by rapid deterioration of symptoms of intracranial hypertension. PFVOO was diagnosed because magnetic resonance imaging revealed an enlarged ventricular system with a barely visible membranous obstacle at the foramen of Magendie. All symptoms were resolved by endoscopic third ventriculostomy. PFVOO should be considered as a rare form of congenital obstructive hydrocephalus, especially in patients with tetraventricular hydrocephalus. To the best of our knowledge, this is the first case of an infant with SIADH, resulting from acute deterioration of non-tumoral raised pressure hydrocephalus.

Magnetic resonance imaging findings associated with lateral cerebral ventriculomegaly in English Bulldogs.

Multiple congenital or developmental anomalies associated with the central nervous system have been reported in English Bulldogs. The purpose of this retrospective study was to identify and describe the prevalence and MRI characteristics of these anomalies and their association with presence and degree of cerebral ventriculomegaly. Magnetic resonance imaging studies of 50 English Bulldogs were evaluated. Forty-eight dogs had some degree of cerebral ventriculomegaly, 27 of which had an otherwise normal brain. Presence of lateral ventriculomegaly was not significantly associated with presence of another intracranial lesion. Appearance of the septum pellucidum was variable, ranging from intact to incomplete or completely absent. The corpus callosum was subjectively thinned in all but three dogs, two of which had normal lateral ventricles. Fusion of the rostral colliculi was not found in any dog. A persistent craniopharyngeal canal was identified in one dog. Aqueductal stenosis caused by fusion of the rostral colliculi was not identified in any dog. Findings indicated that cerebral ventriculomegaly is a common finding in English Bulldogs with or without other intracranial lesions, aqueductal stenosis caused by fusion of the rostral colliculi is unlikely to be a common etiology leading to obstructive hydrocephalus, and a large craniopharyngeal canal is a rare finding that has unknown clinical significance at this time.

[Congenital medulloblastoma associated with intracranial arachnoid cyst]. / Meduloblastoma congénito asociado a quiste aracnoideo intracraneal.

Arachnoid cysts are very common lesions in paediatric patients, with treatment depending on their location and symptomatology. They are usually solitary cysts but may be associated with other central nervous system diseases such as tumours and congenital deformities. We describe the case of a neonate diagnosed with an arachnoid cyst of the quadrigeminal cistern treated by endoscopy. After the operation, the child's condition worsened; a CT scan revealed a midline posterior fossa tumour not visible in the preoperative neuroradiological tests. The tumour, a medulloblastoma, was partially removed. Given the child's age and the poor prognosis, oncological treatment was not undertaken. The association between medulloblastoma and arachnoid cyst is very rare, and we could find only one such case in the literature.